Modeling, Design, and Implementation of a Power Conversion System for Small-Scale High-Altitude Wind Power Generating System

This paper presents a compact portable power conversion system (PCS) for small-scale high-altitude wind power (HAWP) generating system. The proposed PCS interfaces the variable voltage and variable frequency ac power to the distribution level grid voltage. The PCS consists of a three-level Vienna rectifier for the generation-side control, a soft-switched half-bridge dc-dc converter for isolation and step down, and a two-level inverter for grid interface. The proposed conversion system uses a smaller number of active semiconductor devices that reduces overall losses, and thereby, increases power density of the converter. The sensorless optimal torque control technique (using d-q frame) with output voltage balance is proposed and implemented for the generation-side maximum power-point tracking control. A modified proportional-resonant-based control method is proposed for grid-side current control. Simulation studies have been carried out using MATLAB and PSIM. A laboratory prototype is developed and tested for a scaled-down model. The experimental results validate the performance of the PCS for interfacing HAWP into the grid/load.